Pump-motor unit



Dec. 24, 1957 E. F. KLl-:sslG ET AL 2,817,210

PUMP-MOTOR UNIT Filed July 21, 1954 f I l z 40 42 '(2 52 |O 24 56 f 28 30 P 34 eo 2 l INVENTORS' ERNST F; KLESSIG [ice 2,817,210

Patented Dec. 24, 1957 PUMP-MOTOR UNIT Ernst F. Klessig, Berkley, MacKellar K. Graham, Detroit, and Ray J. Raupp, Birmingham, yMich., assignors to Airway Products, Inc., Pontiac, Mich., a corporation of Michigan Application July 21, 1954,. Serial No. 444,894

Claims. (Cl. Gil-52) The present invention relates to a -pump motor unit, and more particularly to `a hand operated-unit `including a reciprocating piston typetpump and reciprocating piston type motor associated therewith.

it is an object of the present invention to provide a a pump motor unit including a pump having an inlet connection including a valve controlled by the motor.

More specifically, it is an object of the present invention to providein combination a pump andmotor including an outlet connection from the pump to the motorand an inlet connection from the .motor to the pump, including a valve responsive to operation of the motor for controlling the inlet connection to the pump.

It is a furtherobject ofthe present invention to provide a pump-motor combination as described in the preceding paragraph including a check valve between V,the outlet of the pump and the inlet to the motor.

It is a furtherobject of the present inventiontoprovide a pump-motor combination as described in thevpreceding paragraph in which the pump includes a reciprocating piston adapted to elect mechanical yopening of the check valve when moved to a 4position beyond its normal pumping stroke.

It is a feature of the present invention to provide a pump cylinder, a motor cylinder,.a pump piston, a motor piston, a first passage Connecting the outletoflthe pump cylinder to one end of the motor piston, a second passage including a iirst port in a side wall of the motor cylinder remote from the end thereof connected to said first passage, and a second port in the side wall of the pump cylinder, the `first port of the second passage being in position to be covered'by the motorpiston when moved to one limiting position, .thepump fpiston having a passage therein including a lirst port registering with the second port of the second vpassage when the pumpis at the end of its suction stroke and asecondtport opening into the end of the pump piston adjacent the connection thereto of said first passage, a check valve at the end of said pump cylinder connected to said tirst passage, said pump piston being movable beyond its normal `pumping stroke into engagement with said check valve to open the same, and a bypass recess in said pump cylinder effective to establish communication between opposite ends of said pump cylinder when said pump piston is `in position to open said check valve.

Other objects and features of the-invention will become apparent as the description proceeds, v*especially A.when taken in ,conjunction with ythe :accompanying drawings, wherein:

Figure 1 is a longitudinal I`sectional ,view V.through the pump-motorunit.

Figure I2 ,is a ,section .on the line ,2-12, :Figure 1.

The pump-motor unit is designed for hand operation and is arranged to effect a slow movement of the operating piston of the motor under the control of lever means actuating the piston of the pump. The unit comprises a main housing 10 having apump cylinder 12 anda motor cylinder 14- orrned therein. Slidably mounted within the motor cylinder 14 is a motor piston 16 connected to a piston rod 18 extending through an opening 20 in a removable cap 22 designed to close one end of both the pump cylinder 12 and the motor cylinder 14.

Slidably mounted in the pump cylinder 12 is a piston 24 having a stem 26 including a cylindrical head 28 slidable in a cylindrical bore 30 provided in the housing 1i). The stem 26 is provided at one side with rack teeth 32 associated with a sector gear 34 operably keyed or otherwise connected to a shaft `36 provided with a handle (not shown) extending therefrom at right angles.

Formed in the housing 1.6 is a Vpassage 38 connecting one end of the pump cylinder 12 to one end of the motor cylinder 1d. At the end of the `pump cylinder to which the passage 38 is connected isprovided a conical enlargement 4u and associated `therewith is a check valve 42 normally retained in closed position by a light compression spring 44 one end of which bears against -the inner surface of the cap 22. Adjacent the othertend of the motor cylinder 14 is a motor outlet port 46 forming one end of a passage 48, the other end of which forms a pump inlet port 50 entering into a side wall of the motor cylinder 12.

The piston 24 is provided with a passage including an axially extending portion 52 opening into the end of the piston adjacent the check valve 42 andincluding an offset portion 54; opening linto a side of the piston and adapted to communicate with the port ,S0 when the pump piston is in its extreme right hand position, close to the position as seen in Figure l. This position of course is the position occupied by the piston at the end of its suction stroke. The interior of the pump ,cylinder12 adjacent to the port 50 is provided with an elongated annular recess 56 for a purpose which will presently appear.

The housing ,10 is provided with an internally threaded projection 58 which receives an externally threaded removable closure member 60 through which the hydraulic uid may be introduced into `the unit.

in operation the unit is `filled orsubstantiallylilled with hydraulic fluid. in the position shown in Figure l it will be observed that the passage through the pump piston is in communication with the passage 4S due to the overlap between the port Sti and the lateral extension 54 of the pump piston passage. The Huid atthis time may flow from the motor cylinder through the passages d8, 5'4 and 52, into the space at the left hand end of the pump piston 24, as seen in Figure l. Oscillation of the shaft 36 in a counterclockwise direction as seenin Figure l, will move the pump piston 24 to the left. After short travel of the pump piston `the passage 54 therein no longer communicates with the port l5t) and accordingly, further movement of the piston-to the left forces the uid to the left of the pump piston past the check valve 42, through the passage 38, vand into the left hand end of the motor cylinder 14, thereby movingv the motor piston 16 to the right. Upon reverse oscillation of the shaft 36 the check valve 42 seats, preventing return iiow of iiuid from the motor cylinder to the pump cylinder. As the pump piston 24 is Imoved to the right the space between the left hand end of the pump pistonand the check valve becomes void since no fluid can flow into this space until the lateral passage 54% inthe pumppiston communicates with the port 50. As soon as this occurs, uid is quickly sucked from the motor cylinder :1:4 through `the passages 48, 54 and 52, into the #space at the :left of the-,pump piston. .The operationmaybezcontinucd until the motor piston 16 Vreaches-fthe position-illustrated ;,in dotted -lines at which time it overlies the port 46, thereby Aclosing the passage 48. Further oscillation of the shaft 36 has no effect since no fluid can flow into the pump cylinder. The advantage of this arrangement is that the pump may be continuously operated and yet will move the motor piston only to a predetermined position after which continued reciprocati-on of the pump piston has no ettect either in moving the motor piston or in developing undesirable pressures within the hydraulic system.

In order to release the motor piston 16 for movement to the left to the full line position illustrated in Figure 1, the shaft 36 is rotated beyond its normal limits of oscillation to cause the pump piston 24 to engage the inner end of the check valve 42, forcing it oi its seat against the action of the spring 44 and permitting fluid to return from the motor cylinder 14 through the passage 38 and past the check valve 42. The end of the pump piston 24 may be provided with radial grooves or channels 62. so that the fluid returning past the check valve 42 may enter the passage 52 in the pump piston 24. At this time the lateral passage 54 of the pump piston will be in communication with the left hand end of the recess 56 and the right hand end of the pump cylinder proper will be to the left of the right hand end of the recess 56 so that a bypass ow of uid from the lateral portion 54 of the passage in the pump piston through the recess 56 and beyond the right hand end of the piston 24 is permitted. The fluid may then pass through the passage 48 into the motor cylinder 14.

The foregoing construction permits the motor piston 16 to be moved to the left and it is contemplated that in use the piston rod 18 may be connected to mechanism including spring means effective to return the piston to the full line position illustrated.

Attention is called to the fact that by oscillation of the shaft 36 the piston may be moved to any required position intermediate the limits of its stroke and will be retained in this position against return movement by closure of the check valve 42. At the same time the piston may be released for return to the full line position illustrated from any desired intermediate position of its stroke by simply moving the piston 24 of the pump to the left to move the check valve 42 olf its seat.

An important feature of the present invention is the arrangement whereby the suction stroke of the pump piston results in cavitation of the space between the operating face of the piston so that as soon as the passage through the piston is in communication with a passage leading to the motor cylinder, the hydraulic liuid will be sucked quickly through the passage in the valve.

Another important feature of the present invention is the provision of a valve controlling inlet ow of fluid to the pump under the control of the motor. By virtue of this arrangement the use of pressure relief valves and additional bypass circuits is completely avoided. While the invention is disclosed as comprising a motor in combination with the pump, it will be understood that so far as this feature of the invention is concerned, instead of a motor other means subject to variable conditions might be employed. Thus for example, the pump could be connected to an accumulator chamber and the valve controlling inlet llow of uid to the pump could be responsive to the pressure in the accumulator chamber so as to render continued operation of the pump ineffective to pump fluid upon attainment of a predetermined pressure within the Vaccumulator chamber.

The drawings and the foregoing specification constitute a description of the improved pump-motor unit in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What we claim as our invention is:

1. A hand operated pump-motor unit comprising a housing having pump and motor cylinders therein, a first passage connecting the outlet end of said pump cylinder to the inlet end of said motor cylinder, a second passage connecting the outlet end of said motor cylinder to said pump cylinder including ports in the side walls of said motor cylinder and said pump cylinder adjacent the outlet and inlet ends thereof respectively, a check valve in said first passage effective to prevent return ow of fluid from said motor cylinder, a piston in said motor cylinder movable on its working stroke to a position overlying the port therein to prevent ow of tluid to said pump cylinder, said pump piston having a passage therein including a first port registerable with the port in said pump cylinder when said pump piston is at the end of its suction stroke and a second port opening into the face of said pump piston adjacent the outlet end of said pump cylinder, said pump cylinder having a recess in its inner wall registerable with said rst port in said pump piston and of an axial extent to connect said second port to the pump cylinder beyond the end of the pump piston adjacent to the inlet end thereof, said check valve being located at the outlet end of said pump cylinder in position to be mechanically opened by said pump piston when its said first port is in registration with said recess to provide for return ow of fluid through the passage in said pump piston from the outlet to the inlet end of said pump cylinder.

2. A pump-motor unit comprising a pump cylinder, a motor cylinder, a rst passage connecting the outlet end of said pump cylinder to the inlet end of said motor cylinder, a second passage including ports in the outlet end of said motor cylinder and in said pump cylinder adjacent the inlet end thereof, a pump piston in said pump cylinder, a motor piston in said motor cylinder, a check valve at the outlet end of said pump cylinder in position to be opened by movement of said pump piston beyond its normal pumping stroke, a valve including a port closed by said motor piston controlling flow through said second passage from said motor to said pump piston, said pump piston having a passage extending from the face thereof adjacent said check valve to a side thereof and registerable with the port of said second passage when said pump piston is adjacent the limit of its suction stroke, said pump cylinder including a bypass recess located to connect the passage in said pump piston to the end of said pump cylinder remote from said check valve when said pump piston is in position to open said check valve.

3. A pump-motor unit comprising a casing having pump and motor cylinders therein, pump and motor pistons in said respective cylinders, a first passage connecting the outlet end of said pump cylinder to the inlet end of said motor cylinder, a check valve at the outlet end of said pump cylinder in position to be opened mechanically by said pump piston upon movement beyond the end of its normal pumping stroke, a second passage including a motor outlet port in the side of said motor cylinder adjacent the end thereof toward which said motor piston moves upon operation of the pump and a pump inlet port in the side of said pump cylinder adjacent the end thereof remote from said check valve, said pump piston having a passage including a first port in the side thereof registerable with said pump inlet port when said pump piston is at the end of its suction stroke and a second port opening into the face thereof adjacent said check valve, said pump cylinder having an elongated recess in the side thereof located to provide a bypass passage from the said irs't port of said pump piston to the end of said pump piston remote from said check valve when said pump piston is moved to position to open said check valve.

4. A pump-motor unit comprising a pump cylinder, a motor cylinder, a first passage connecting the outlet end of said pump cylinder to the inlet end of said motor cylinder, a second passage including ports in the outlet end of said motor cylinder and in said pump cylinder adjacent the inlet end thereof, a pump piston in said pump cylinder, a motor piston in said motor cylinder, a check valve at the outlet end of said pump cylinder in position to be opened by movement of said pump piston beyond its normal pumping stroke, a valve including a port closed by said motor piston controlling flow through said second passage from said motor to said pump piston, said pump piston having a passage extending from the face thereof adjacent said check valve to a port registerable with the port in said pump cylinder when said pump piston is adjacent the limit of its suction stroke, said pump cylinder including a bypass recess located to connect the passage in said pump piston to said port in said pump cylinder when said pump piston is in position to open said check valve.

5. A pump motor unit comprising a pump cylinder having a fluid outlet port, a motor, a reservoir for fluid, a rst passage for carrying uid from said outlet port to said motor to actuate the latter, said pump cylinder having an inlet port spaced axially of said pump cylinder from said outlet port, a second passage from said reservoir to said inlet port, a check valve in said rst passage for preventing return flow of fluid to said pump cylinder, said motor having a part adapted to close said second passage upon a predetermined actuation thereof to prevent flow of fluid to said pump cylinder, said check valve being located in a position to be opened by said piston upon movement of said piston beyond its normal pumping stroke, said piston having a passage extending from its face adjacent said outlet port to a port registerable with said inlet port when said piston is adjacent the limit of its suction stroke, said pump cylinder including a bypass recess located to -connect the port in said piston passage to said inlet port when said piston is in position to open said check valve to connect said outlet port to said inlet port.

References Cited in the file of this patent UNITED STATES PATENTS Re. 13,483 Kingwell Oct. 29, 1912 1,663,647 Brush Mar. 27, 1928 2,557,880 Lynn June 19, 1951 

